Patent document BR PI 0703605-1 (A), to Ayala Barreto, which is incorporated by reference herein, describes a drying process of sensitive solids, such as seeds and other agricultural products, or solids requiring low temperature drying, in a clean environment and free from contaminations, allowing the storage of agricultural products safely, including in the intense tropical and subtropical weathers, and also allowing a better control on the properties of the air treated by such device, regardless of the outside weather, thus providing functional improvement and more flexibility in its use.
As it is of the knowledge of the technical mean related to the agricultural sector, especially the segment of storage of grains and seeds, there is a demand for alternative solutions for the drying process of these products, aiming reduction of loss and maintenance of the physiologic and sanitary quality of the products, from the harvest to their industrialization or sowing (in case of seeds). In the industry, other solids sensitive to temperature may use this process, since the low temperature and low humidity drying air keep the characteristics of the products.
The equipment disclosed by the patent document PI 0703605-1 is provided with an air dryer with pleated air filter (1) of large capacity for the retention of dust and air impurities, evaporator serpentine (2), compressor (3), centrifugal fan (4), condenser (5), and primary air outlet duct (6), command panel (7), outer air intake damper for mixture (8), power panel (9), outlet air temperature sensor (10), outlet air relative humidity sensor (11), outlet air temperature PID controller (12), outlet air relative humidity PID controller (13), frequency inverter for compressor (14), evaporator outlet air temperature sensor (15), outlet air temperature PID controller of the evaporator (16), frequency inverter (17), cooling fluid expansion valve (18), intake air temperature sensor (19), intake air relative humidity sensor (20), enthalpy calculation processor (21), and main processor (22).
The functioning of the process and the device of the patent document PI 0703605-1 occurs as follows: air humidity is extracted from the condensation of the water vapor in the evaporator serpentine and the relative humidity is reduced by the addition of sensible heat into the condenser serpentine. The modulation of the frigorific power from 0 to 100% occurs automatically by means of the frequency inverter, or step motor, or DC motor, or hydraulic motor, from signals coming from the outlet air temperature PID controller (12) and the outlet air relative humidity PID controller (13).
The device of the patent document PI 0703605-1 has met the expectations, however, within a policy of ongoing improvement, further research and development conducted culminated in the obtainment of a functional improvement and greater flexibility of use.